Hi Hamiora,

WebTab does not support reloading content of a random/specific tab. Async postback can be triggered from client, but server will not update content of a random tab. Server follows exact rules defined by PostBackOptions, but not actions on client.
Below are some scenarios when EnableAjax is set and EnableLoadOnDemand is not set:
1. If EnableReloadingOnTabClick is set, then if user clicked already selected tab, then that content of selected tab will be updated.
2. If EnableReloadingUnselectedTab is set, then content of previously selected tab will be updated. So, if user will select that tab again, then it will have latest server data.
3. If new tab is selected, then content of that new selected tab is not updated.

If application needs to update selected tab at the time when it was selected and work only with server properties, then it should use EnableAsyncUpdateAllTabs or EnableLoadOnDemand.
Application also may trigger "reload" action from client which will be equivalent to user click on already selected tab. The set_selectedIndex(index, reload) on client supports second "reload" parameter. But UpdatePanel (or url) will be updated only if that index is equal to already selected tab, because of rules on server, which I mentioned. Below is example:

<script type="text/javascript">
function reloadTab()
{
 var tab = $find('<%=WebTab1.ClientID%>');
 var index = tab.get_selectedIndex();
 tab.set_selectedIndex(index, true);
}
</script>
<input type="button" value="ReloadSelectedTab" onclick="reloadTab()" />

The webtab also has few internal methods which do actual reloads. They can not be exposed publically, because they may have effect only in very specific situations. The _doAjax(index) will trigger async postback for a tab which has UpdatePanel. So, if application knows exactly that a specific tab is selected and it has UpdatePanel, then it may use that internal method (no support in case of misbehavior). For example, it may use it within ClientEvents.SelectedIndexChanged or explicitly on external event instead of set_selectedIndex(selectedIndex, reload).
Below are 2 examples.

Trigger ajax on external event:

<script type="text/javascript">
function reloadTab()
{
 var tab = $find('<%=WebTab1.ClientID%>');
 var index = tab.get_selectedIndex();
 if(index == 1 || index == 2)
  tab._doAjax(index);
}
</script>
<input type="button" value="ReloadSelectedTab" onclick="reloadTab()" />

Trigger ajax within selected tab changed.

<script type="text/javascript">
function WebTab1_SelectedIndexChanged(sender, eventArgs)
{
 var index = eventArgs.get_tabIndex();
 if(index == 0 || index == 1)
  sender._doAjax(index);
}
</script>
<ig:WebTab ID="WebTab1" runat="server" Width="321px" Height="200px">
  <Tabs>
   <ig:ContentTabItem runat="server" Text="Tab 1" UserControlUrl="WebUserControl1.ascx"></ig:ContentTabItem>
   <ig:ContentTabItem runat="server" Text="Tab 2" UserControlUrl="WebUserControl2.ascx"></ig:ContentTabItem>
   <ig:ContentTabItem runat="server" Text="Tab 3"></ig:ContentTabItem>
  </Tabs>
  <ClientEvents SelectedIndexChanged="WebTab1_SelectedIndexChanged" />
  <PostBackOptions EnableAjax="True" EnableReloadingOnTabClick="True" />
</ig:WebTab>

Ok. I just want to reload the entire tab, regardless of the content, without having to click on a previously selected tab twice (It's not very intuitive otherwise).

If EnableReloadingOnTabClick is enabled, any tab, including a UserControl tab can be reloaded via AJAX postback on the client-side by clicking twice on the previously selected tab. Could the action that triggers the postback, be triggered in client-side in the SelectedIndexChanging event too? 

Hi Hamiora,

The UserControlUrl means name of UserControl which is nothing more than a template which fills child control similar to controls defined in aspx. You may think of it, as if you drop a user control on aspx. It is not possible to reload only that control from client.

Hi Viktor. What if the tab that needs to be reloaded is a UserControlUrl not a ContentUrl. When using your method above, I'm having trouble trying to find how to reset the UserControlUrl as the tab contains a div not an iframe for user controls.

Thanks!

Viktor, absolutely perfect!  I use iFrames pretty heavily inside the tabs, and this is a recurring issue on several of my pages.  This effectively solves the problem.

Thanks!  You are the guru!

-Rob